John Randall — Geology of Linley Valley. 495 



8. Followed by eleven inches of micaceous sandy grits, with 

 Lingulce. 



9. Greenish, irregularly laminated rock with conglomerate, one 

 foot. 



10. Hard calcareous grit, with thickly disseminated grains, and 

 many broken Lingidce, twelve inches. 



11. Succeeded by twenty feet of laminated light grey micaceous 

 grit; and — 



12. Lastly, about six feet of micaceous sandy clays coloured by 

 peroxide of iron. 



These are the lowest traceable in the glen or gorge, where the 

 first Bone-bed occurs, and they are succeeded, I imagine, although 

 the connexion is not to be very distinctly traced, by the yellowish 

 sandstone seen beneath the yew-trees higher up the brook, which is 

 probably of the Downton series. It contains BeijricMcB and Zingulce, 

 the former in abundance, and in one or two ferruginous bands may 

 be found dermal scutes of Thelodus, with fragments of Lingulce. 



The " Lower Bone-bed " then occurs in the bed of the brook, in 

 conjunction with a hard calcareous rock containing numerous clusters 

 of llodiolopsis complanata at its base ; and to these succeed flaggy 

 beds of impure limestone containing Serpidites longissinms and other 

 Upper Ludlow forms, followed by the Aymestry series, which, how- 

 ever, become much better developed on the sides of the Caughley 

 division of Darley Brook, a stream entering the Severn a few hundred 

 yards higher up, and where characteristic fossils such as Bhynchonella 

 Wilsoni, Bhynchonella spherica, Chonetes lata, with others, are to be 

 found. 



Among the fish fauna of these beds, Sir Philip Egerton has dis- 

 tinguished remains of Onchus, Plectrodiis, Ctenacanlhus, and I think 

 others. 



It is worthy of remark that Plectrodus, Onchus and Ctenacanlhus 

 abound most as characteristic of this zone, and that at Ludlow the 

 Crustacean remains of Pterygotus predominate, while at Ledbury the 

 Cephalaspid fishes seem to have been the chief inhabitants of the 

 water. 



The "Upper Bone-bed" is interesting as connected with the 

 extreme northerly extension of one great section of the Old Ked 

 Sandstone, which, following an uninterrupted course from South 

 Wales, through Herefordshire and South Shropshire, and attaining a 

 thickness of several thousand feet, here dwindles down to the compass 

 indicated, and speedily disappears altogether. 



Similar " Bone-beds," with Devonian and Silurian passage shales, 

 have been found in Herefordshire, Worcestershire, and Gloucester- 

 shire, the latter at Pyrton Passage, a point about 70 miles distant 

 from Linley. 



Whether these beds, which are never more than a foot in thickness, 

 and more frequently are not more than one or two inches, are abso-^ 

 lutely continuous or not over all the intervening spaces between 

 the points indicated, there is no evidence to show. In either case 

 they point to a uniformity of conditions over large areas, and indicate 



